The present invention relates generally to railroad maintenance machines, and more specifically to a railway plate inserter workhead for inserting rail plates under rail ties.
Conventional railroad track consists of a plurality of spaced, parallel wooden ties to each of which are attached a pair of spaced rail tie plates. Each tie plate is configured to rest on an upper surface of the tie and includes holes for receiving fasteners such as spikes or screws, as well as a canted seat or a cradle formation for receiving the foot or base of the steel rail. Since two rails make up a railroad track, there is a pair of spaced tie plates on each tie. As is known in the art, some of the fasteners are used to secure the tie plate on the tie and others secure the base of the rail to the tie plate cradle.
When replacing worn ties, or when laying new rails on a pre-existing railroad track bed, tie plates are positioned on the railroad ties. One plate is required for each rail on a tie and the plates are initially placed adjacent the track, either by a crane or by a work gang. The plates are then non-accurately positioned upon a top surface of the tie to receive the rail.
In conventional railroad track maintenance, the plates are manually centered on the tie, then positioned under the rail to receive the foot of the rail in the recess of the plate. As part of this process, the rail is lifted from the tie to properly position the plate. It will be appreciated that such manual placement involves high labor costs, inconsistent accuracy of placement, and is time consuming.
Railways have attempted to mechanize at least portions of the plate insertion process. However, such systems have not been widely accepted by the railroads because of the relatively complicated mechanisms involved in performing the insertion. Additionally, conventional insertion machines are unable to accommodate irregularities in plate sizes and shapes. For example, plates used on curved track are larger than plates used on straight track. Deviations of as little as ⅜of an inch in the plate are significant in automatic plate insertion machines. Due to these variations, frequent manual readjustment of settings is required in conventional plate handling equipment to accommodate different sizes and shapes of plates.
Railroad installation and maintenance machines typically include a workhead that pushes a previously placed tie plate underneath a rail tie. These conventional machines are unable to account for plates misaligned on the tie. Further, in cases where the plate inserter incorrectly pushes the plate underneath the tie, a worker is typically required to manually retrieve the plate under the tie, which is time consuming. Since plate handling machines are commonly one of a caravan of maintenance machines, the productivity of the maintenance of the railroad maintenance gang is limited as measured by the rate of the slowest unit.
Accordingly, there is a need for an improved plate inserter which reduces the manual handling of plates during the plate insertion process, and which addresses the above deficiencies of conventional plate insertion techniques and equipment.